1. Field of the Inventions
The invention generally relates to video decoders, and more specifically to decoding of composite input video signals.
2. Description of Related Art
There is a large surge in the use of digital video devices today. Examples include: digital televisions, LCD TVs and monitors, DVD recorders, personal video recorders, PC video cards, video capture and streaming applications, and video conferencing. In many cases, these units need to receive an analog video signal, which may be one of the composite signals, such as NTSC, PAL or SECAM; s-video; component video or RGB. It is then desirable to produce the proper digital output, such as eight or ten bit ITU-R BT 656. It is preferred that all the video decoding be done in a single chip for all of these formats. The decoder not only has to handle composite signals, which means it must be able to determine the chroma and luma values, but it also must handle vertical blanking interval (VBI) data and handle VCRs, which are unstable devices.
In many cases, accuracy of the composite decoding is reduced due to clocking errors and noise injection in conventional decoding designs. It is desirable to improve the decoding accuracy.